Coal-washing process and plant



April e, 1926. 1,579,295

A. FRANCE COAL WASHING PROCESS AND PLANT Filed August 1, 1924 Patented Apr. 6, 192$,

ANTOINE FRANCE, OF LIEGE, BELGIUM.

COAL-WASHING PROCESS AND PLANT.

Application filed August 1, 1924. Serial No. 729,502.

To all whom it may concern:

Be it known that I, ANTOINE FRANon, engineer, a subject of the King of the Belgians, residing at Liege, Belgium, 17 Quai Saint Leonard, have invented new and useful Improvements in Coal-Washing Processes and Plants, of which the following is a specification.

The resent invention relates to improvements 1n processes and plant for washing coal, and more particularly in plant of the kind comprising a launder wherein the products are subjected to the action of a conveying stream and along which are artl5 ranged upward stream separators with adjustable discharge apertures, which according to the purpose which they serve,

may be considered as forming two consecutive series each comprising one or more separators.

The re-washing of the ,slaty material or impurities discharged by the first series (i. e. that closer to the point of introduction of the raw material into the launder) of the separators of a launder is justified inimportant installations to recover the clean coal which may be accidentally discharged with the schists, and it is all the more justi fied in all installations when the nature of the raw coal is such that the production of mixed products is required to obtain on the one hand suificiently clean coal and on the other hand schists free from still useful middlingsfor'bone.

It has previously been proposed, as described for instance in U. S. A. patent specification.No. 1,492,025, in plants comprising at least two series of one or more upward stream separators with adjustabledischarge 40 apertures arranged along a launder, to provide for an elevator or like mechanical means to take up the products discharged by th (e second of the said series of separators and to return same to the top of the launder; the present invention isessentially characterized by the combination with such an installation or washing installation proper of an installation for re-washing the impurities or slates, constituted by a second launder along which are arranged two con- .p into theboot v of the elevator e, which secutive series o-f-one or more upward stream separators with ad ustable discharge aper.-

tures,' 'and into the upstream end otwhich. the elevator or like, mechanical dev ce delivers th impi e. (s a es) .v th rew through the first series of the separators of the washin launder proper, the products discharged y the last series of the separa;

..tors of the said second launder being returned to the upstream end of the washing launder proper like those withdrawn through the last seriesof separators of this lastnamedlaunder.

An embodiment of plant according to the invention is, by way of example only, illustrated by the accompanying purely diagrammatic drawing, wherein Fig. 1 shows a plan and Fig. 2 an elevation of an installatlon wherein thetwo series of separators arranged along each of the two launders each comprise a single separator, it being understood that each series may as well consists of two or more separators, Figure 3 showing, for purely illustrative purposes, one construction of the separators included in the plant according to the invention.

As shown in Figures 1 and 2, the plant comprises a washing launder proper a along which are disposed two upward stream separators b and c the latter of which has its adjustable discharge mouth delivering at (13 into the boot of a bucket elevator e which, by way of a chute f, pours the collected products into the top or upstream endot the launder a, i. e. at the point where the 55 raw product to be treated is fed thereto and upstream in relation to. the position of the .first separator I). This washing installation proper is according to the invention c0mbined with an installation for re-washing the slates comprising a second or re-washing launder 9 along which are also disposed two upward stream separators h and '11 with adjustable discharge aperture. This re-washing installation also comprises a bucket elevator k, of which the boot or sump is arranged under the discharge. aperture m of the first separator b of the launder a, and which, by way of a chute 'n, delivers the collected products into the top or upstream end of the second launder g, and therefore upstream in relation to the position of the first separator h depending from the said second launder g. Th s second separatora' of this last-named launder discharges at therefore collects both the products discharged-by the separator cof thev launder a and those discha-r ed b the separator a oi; the launder'g. bu et elevator r orother suitable device is provided to remove the shale which is discharged by the separator h.

The particular construction of the upward stream separators with adjustable discharge apertures forms no part of the present invention, but the type illustrated by Fig. 3 may be adopted with advantage. As shown in the said figure, each separator forms a chamber 6 in communication with the launder and of which the lower portion is of trapezoidal shape in the vertical plane passing betweenthe sides of the launder. In the upper portion of said chamber is arranged a downwardly inclined screen t, and water for the upward streams is admitted under said screen by means of a valve-controlled supply pipe u. The discharge of the material accumulating in the upper portion of the chamber 1) is controlled by means of a sector-shaped flap 1) pivoted about a horizontal axis extending along the lower edge of the screen t and to which an oscillatory motion is imparted in any suitable manner, for instance by means of suitable connections w actuated in any convenient manner. The size of the free portion of the discharge opening left between the flap v and the wall of the chamber Z) may be adjusted by varying the position of a vertical bafiie a: movable in a horizontal direction and having its upper portion bent at right angles against the bottom of the launder, the adjustment of the said bafiie w being effected by means of a threaded rod 3 provided at its free end outside the separator with a handwheel z and passing through a threaded nut forming a part of a bracket y fixed to the corresponding wall of the separator.

Referring again to Figs. 1 and 2, the first separator b of the launder a is intended to withdraw slates which are still imperfect that is to say which may still contain a certain portion of clean material and are collected by the elevator and delivered into the top end of the rewashing launder g. The second separator c of the launder a is used to withdraw a mixed product which by means of the elevator e is returned to the top end of the said launder a, where, by mixing with the initial raw product, it exerts a regularizing action similar to that of a flywheel of an engine, and therefore has an influence operating to cause a compensation to take place of the irregularities in the nature of the feed, so that the said elevator 6 may appropriately be called a regularizing elevator. There is thus obtained at the end of the launder a down stream in relation to the position of the separator c absolutely clean coal. In the re-washing installation, the first separator h of the launder'g serves to remove pure slates which are collected and led away by the elevator 1'.

As to the se nd separator 2' 0f the re-Wash ing launder g, it operates in a different manner according to the object to be attained.

Thus, if the re-washing of the imperfect slates in the re-washing installation is carried out with a view to recovering the clean coal and adding the latter to the clean coal obtained at the downstream end of the first launder a, the separator i is adjusted to discharge the whole of the product which is refused by the separator h and is, together with the product discharged by the second separator c of the launder a, returned to the top of this last-named launder by the common regularizing elevator e. In such a case, the launder 9 only delivers at its end downstream in relation to the position of the separator i the water from the conveying stream of the said launder g and the upward stream of the separators h and i.

In the case, however, where the re-washing of the slates is effected in view of obtaining a separate class constituted by the middlings, that is to say a category of products distinct from the clean coal, the separator i is so adjusted as to refuse such properly constituted middlings (which are carried off downstream towards the lower end of the launder g) and to withdraw and discharge the subsisting mixed products, which are collected by the regularizing elevator 6 common to both installations and are returned by the said elevator to the top of the launder a of the washing installation proper, where they accentuate the regularizing effect contributing by compensation of irregularities in the nature of the feed to the maintenance of a regular thickness of the layer of slates in the aforesaid launder favourable to the attainment of an increase in the etficiency of the treatment.

I claim:

1. The process of washing coal consisting in subjecting the imperfect slates, withdrawn in the first instance from an initial washing in a liquid conveying stream by means of upward streams, to an independent re-washing also in a liquid conveying stream, and in bringing back to the point of supply of the raw product, in order to be subjected together with the latter to the initial washing both the mixed product intentionally withdrawn from the said initial washing subsequently to the withdrawal of the slates to be re-washed and the mixed product intentionally withdrawn by means of upward streams from the aforesaid rewashing of the imperfect slates after elimination of the pure slates.

2. In plant for washing coal, of the type comprising a Washing installation proper including a launder for a liquid conveying stream with two series of upward stream separators with adjustable discharge apertures, and an elevator to take up and bring back to the upstream end of the aforesaid launder the products discharged by the last of the two said series of separators, the combination with the said washing installation proper of a re-washing installation comprising a re-washing launder for a liquid conveying stream, an elevator arranged to bring to the upstream end of the said re-washing launder the products discharged by the first of the two series of separators of the washing launder, two series of upward stream separators with adjustable discharge apertures, arranged along the aforesaid re-washing launder, the separators of the last of the two last-named series having their discharge mouths connected to the same elevator as that which takes up and brings back to the upstream end of the washing launder proper the products discharged by the last of the two series of separators depending from the last named launder, and an elevator connected to the discharge mouths of the separators of the first of the two series of separators of the aforesaid re-washing launder.

In testimony whereof I sign hereunto 25 my name.

A. FRANCE. 

